This invention relates to a method and arrangement for automatically positioning a working implement, such as a drill bit, to predetermined positions and/or predetermined directions in space, wherein said predetermined positions and directions are defined by given values of respectively coordinates and an angle or angles in a system of coordinates.
The invention may to advantage be used for rock drilling, which means that the working implement is a drill bit. The invention, however, is applicable generally to positioning of different types of working implements, for instance for controlling of industrial robots.
When applying the invention to rock drilling it is, due to the irregularities of the rock surface intended to be worked, necessary to undertake measures in order to safeguard that the drill bit does not get stuck during movement from one predetermined position to another. According to one aspect of the invention the predetermined positions are programmed such that they are in an imaginary plane which is spaced from the rock surface.
A further object of the invention is to provide an automatic movement of the working implement to programmed positions according to a pattern, such as a drilling pattern, such that the working implement is moved to a predetermined position and/or is adjusted to a predetermined direction in shorter time than is obtainable in hitherto known constructions for automatic movement of a working implement.
To this end, the actual values of the coordinates and/or the angle or angles are sensed continuously. According to another aspect of the invention, the sensed actual values are adjusted simultaneously toward the values programmed in advance. In doing so, a considerable saving of time is achieved when comparing with constructions where the different means for moving the working implement are actuated in turn.